Schmalstig Jainandan 2021 AJB duckweed Figs 1-4.xls

<b>Data for Figures 1-4 and Figures 5-9, Table 1 from article in American Journal of Botany 2021</b><b>Green light attenuates blue-light induced chloroplast avoidance movement</b> <b> in <i>Arabidopsis</i> and duckweed</b> Judy G. Schmalstig^* andKenneth Jainandan Department of Biology, 1000 Holt Ave, Rollins College, Winter Park, FL 32789 ^*Correspondence: [e-mail] <b>ABSTRACT</b> <b>PREMISE:</b> Chloroplast movement to the anticlinal walls in excess light, referred to as chloroplast avoidance movement, is one strategy to prevent high light damage. Chloroplast avoidance movement is mediated by the blue light photoreceptor phototropin. Since some blue light effects are reversed by green light, we investigated the effect of green wavelengths on chloroplast avoidance. <b>METHODS:</b> Chloroplast position was visualized via microscopy and by transmission of red light through the leaves of <i>Arabidopsis thaliana</i> L. and duckweed (<i>Landoltia punctata </i>(G. Mey.) Les &amp; D.J. Crawford). <b>RESULTS:</b> Green light reduced blue-light induced chloroplast avoidance movement but only when green light was presented simultaneously with blue light. Green light alone had no effect on chloroplast position. An action spectrum for green light attenuation of chloroplast avoidance in duckweed revealed peaks at 510, 550, and 590 nm. Blue-light induced chloroplast avoidance movement in three <i>Arabidopsis </i>mutants with reduced nonphotochemical quenching, <i>npq1, npq4 and npq7</i> was not affected by green light. <b>CONCLUSIONS:</b> The action spectrum does not conform to any known photoreceptor. The lack of a green light response in the <i>npq</i> mutants of <i>Arabidopsis</i> suggest a possible role for the xanthophyll cycle or a signal from the chloroplast in control of chloroplast avoidance movement. <br>